oldsparky52
Senior Member
- Location
- Wilmington, NC USA
Are you willing to share the correct answer to my perceived question? What degree is V1 at when V1 to V2 is 208.
Three-phase calculation confusion
- Thread starter Coppersmith
- Start date
- Status
Are you willing to share the correct answer to my perceived question? What degree is V1 at when V1 to V2 is 208.
Strathead
Senior Member
- Location
- Ocala, Florida, USA
- Occupation
- Electrician/Estimator/Project Manager/Superintendent
How about I give you a clue. Look at the stationary sine wave that was posted or find one on the internet. Pick any point in time and measure the distance between two phases, then pick any other point in time and measure the distance between the same two phases. What is the result? That distance is the graphic representation of the voltage potential.
oldsparky52
Senior Member
- Location
- Wilmington, NC USA
If I had the tools to measure that I would have done it instead of asking. Since the sign wave is not linear, I can't measure it with a scale and I have not seen a graph that had enough voltage markings on the Y axis and degree markings on the X axis to make a good guess.
I guess I could try to copy/paste a drawing into a CAD program, but I'm not so sure I'd get the scale correct.
If I could work the formula for the instantaneous voltage on the sine wave, then I wouldn't need a graph. I thought it would be easy to get that answer here, but either I'm just not asking it correctly enough or the answer is quite elusive. Either way, UNCLE!
- Location
- Connecticut
- Occupation
- Engineer
oldsparky52
Senior Member
- Location
- Wilmington, NC USA
Thank you David!
Strathead
Senior Member
- Location
- Ocala, Florida, USA
- Occupation
- Electrician/Estimator/Project Manager/Superintendent
I'm sorry, and my point was actually wrong. I assume there is one or two people here who can answer your question. Regretfully, the one person everyone knows could have answered you is Smart$ and he passed last year. Your question is a very deep math question and if I could remember all of my algebra and trigonometry then I think the answer lies there. At any point in time the three add together, ignoring negative numbers to total the same amount so if your reference is A phase, and it is at zero B phase is going up, then B and C are equal and opposite the zero line. go a little further in time and one of those phases is dropping toward zero getting steeper and the other phase is going away from zero getting shallower. At any time though, I am pretty sure the sum of all three is the same.
- Location
- Connecticut
- Occupation
- Engineer
At any point in time, the sum of all three equals zero.
kwired
Electron manager
- Location
- NE Nebraska
If the heat strips can run while heat pump is running.
Most that do run at same time only do so during defrost cycle, technically code doesn't say you can disregard that, reality - doesn't last long enough that it is really much of a problem, compressor might only be drawing half of RLA at the most in many cases as well.
Fnewman
Senior Member
- Location
- Dublin, GA
- Occupation
- Sr. Electrical Engineering Manager at Larson Engineering
If the panel is 3 phase, it is unlikely that the voltage will be 240 - probably 208 or 277.
kwired
Electron manager
- Location
- NE Nebraska
Not really automatic in many places I work at. There is a lot of 240 volt delta around here.
Coppersmith
Senior Member
- Location
- Tampa, FL, USA
- Occupation
- Electrical Contractor
I just did a job today with a three phase panel. It was definitely 240 volt phase to phase.
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